I have a powered Universal I. I was using it the other day, and it was behaving just fine. At one point, the carriage stopped moving when I engaged the switch. I checked, and one of the 1/2A fuses had blown. I replaced the fuse and it blew immediately upon powering up the press (i.e. I didn’t engage the carriage yet). From the schematic it looks like the only thing it could be is a shorted carriage motor – there’s not much more attached to the 1/2A fuses and rectifier.
Is there some other issue that could be causing this? I’d really rather not have to replace the carriage motor!
Thanks,
-Erik
Saltgrass Printmakers
I’m not 100% sure this is what the advice from The Arm press was talking about, but I have removed the carriage drive motor, and pulled the (very packed) wires from the cavity where the wires from the motor meet the wires of the bundle going back to the Vandercook electronics. 8 wires in all.
You can see some exposed copper on the blue S2 wire to the series field, and the A2 black wire to the motor. I will also check carefully the green and orange wires that go to the shunt field since that’s the part of the circuit that seems to be directly connected to the 1/2A fuses. The black wires to the motor itself seem to be solid.
Strangely, the black A2 wire is connected to A1 on the motor, and the white A1 wire is connected to A2 on the motor! That seems like it would cause the motor to spin the wrong way. But, I suspect I should reconnect things they way they are now since it was working (until recently).
So, my next step is to clean the wires, get rid of the electrical tape, redo all the connections, and seal with insulated shrink tubing. and see what happens. I hope I can reinstall the motor without too much hassle!
Helpful person from The Arm – is this what you were talking about? Any additional advice at this point?
Thanks!
thanks! That sounds really intriguing as a possibility. Of course I would much rather not take the motor apart, but I am comfortable with electronics and heat shrink, etc. years ago I replaced all the contactors and micro switches on this particular press. I will definitely check this out and report back, but won’t be able to get into the studio until next week sometime.
A common point of failure is the shrouding where the individual wires exit the motor. It disintegrates to dust and the copper wire shorts against the other wires or against the motor body itself.
While the wires can’t be properly replaced without disassembling the motor, we have found a fix in fitting lengths of heat shrink insulating tubing over the wires and shrinking it with a heat gun.
To do this, we had to remove the motor and put it on the workbench. I am not suggesting that you dig into this if you don’t feel confident with electricity, but it is something that has gotten us out of a similar pinch with a press in our own shop.
If you do get in there at all, please be sure to unplug the machine from the wall. And keep in mind that when the motor is tipped on its side, you are likely to lose gearbox oil if you still have any.
We’ll be waiting for your update.
You make good points Paul – I don’t know about the age of the fuses I tried. They might be old. I’ll try a new one, but I suspect the result will be the same…
I’m not aware of a specific test, but I’ve alerted other Universal Power owners to your post.
I trust that Erik knows, but for the benefit of other users factors affecting fuses include:
Also, is there something I can do to pin down the problem? That is, is there an easy test to see if it’s the motor or something else?
Thanks again,
-Erik